The network elements in a data network are often arranged to transmit and receive digital data flows representing various data transmission protocols. A network element, such as a loop access multiplexer arranged in a mobile phone network, can be for example arranged to connect both packet switched 10/100 Ethernet traffic and time slot switched E1/T1 traffic. Ethernet is described for example in the technical specification IEEE802.3 (Institute of Electrical and Electronics Engineers), E1 is described for example in the technical specification ITU-T G.703 (International Telecommunications Union), and T1 is described for example in the technical specification ANSI T1.102 (American National Standardization Institute).
In practical operation environments of network elements it is typical that some operation environments need a lot of 10/100 Ethernet connections and only a small quantity, if at all, of E1/T1 connections. Respectively some other operation environments need a lot of E1/T1 connections and only a small quantity, if at all, of 10/100-Ethernet connections. The described mutual differences between various operation environments must be taken into account when planning the structure and production of network elements.